In the case of using a digital triax system for transmission of video signals in a studio of a television station or the like, a high-definition video (HD return video) of another camera on the air or a standard-definition video (SD prompter video) for announcer script may be inputted to a camera control device, transmitted to a camera adaptor through a triax cable, and outputted to a view finder of the camera and a script projection device.
Unlike an optical fiber cable, the triax cable does not have a signal transmission band that allows uncompressed transmission of high-definition video. Thus, conventionally, the return video and the prompter video are compressed at a low bit rate by using a codec (image compression/decompression device) and then transmitted.
As for an example of a conventional technique Japanese Patent Application Publication No. 2010-135882 discloses a technique of minimizing transmission loss and transmission delay by defining a data transmission region where a compressed return video and a compressed prompter video are combined and varying the size of each transmission region in response to increase/decrease in the compressed prompter video data and the compressed return video data.